A conventional fuel, such as liquid or gaseous hydrocarbons or alcohols, can be converted to hydrogen by a reforming process to provide an energy source to a fuel cell. In a typical reforming process, a fuel, water steam, and/or air are vaporized and mixed. The mixed gases are passed over a catalyst in a reforming reactor to convert the fuel into a reformate, i.e., a reforming reaction product that contains hydrogen, carbon monoxide, carbon dioxide, and unreacted water. Subsequently, carbon monoxide in the reformate is substantially removed by contacting the reformate with another catalyst. This reaction, referred to as the “water gas shift reaction,” is typically done at two stages: a first high-temperature stage and a second low-temperature stage. The reaction at the high-temperature stage is normally conducted at a temperature significantly lower than that found in a reforming reactor. Thus, cooling of the reformate is required before the water gas shift reaction occurs at the high temperature stage.